Along with the spread and improvement in data transmission rates of communication networks such as the Internet, a remote communication system by which a TV conference is carried out between remote locations has come into use. By using the remote communication system, it is possible to reduce business trip costs and business trip man-hours.
In the remote communication system by which a TV conference can be carried out, image data and voice data are transmitted between plural remote communication terminals directly or using a server. Thanks to recent fullness of the broadband environment, transmission of image data with high image quality and voice data with high sound quality becomes possible. Thereby, a situation of another person in a TV conference becomes able to be easily understood, and it becomes possible to understand each other by conversation at a high level.
By using such a remote-communication system, not only voice data and image data but also display data of material used for a conference is transmitted to another person in the conference by using a certain apparatus (for example, an external input apparatus) in some cases. Because of transmitting the display data of the material, another person in the conference can see the same material as that of this side (for example, see U.S. Pat. No. 6,760,749).
However, as the number of remote communication terminals being used in a TV conference increases, the number of sets of material to be shared by the respective remote communication terminals increases. As for this point, according to U.S. Pat. No. 6,760,749, material to be displayed is selected as a result of conference participants selecting the material to be displayed from among plural sets of material by designating corresponding URLs (Uniform Resource Locators).
However, if a user needs to select material to be displayed on a remote communication terminal, operating performance may be degraded. For example, at each time when a certain user switches material, another user needs to designate the material by using the URL, and display the material on the own remote communication terminal.
On the other hand, when all of the sets of material which are sharable and the sets of material which are likely to become targets of discussion are displayed on the display device of the remote communication terminal after reducing the sizes or using the respective windows, a display area for each set of material is reduced in size or the display areas are overlapped and thus, viewing ability may be degraded. Further, it may become difficult for each user to determine which one of the sets of material is the target of the current discussion.